US2598736A - Refrigerator of the absorption type - Google Patents

Description

2 SHEETS-SHEET 1 /l/ MIb/imola.

BY if? E I Tram/Ey June 3, 1952 N. E. wlDELl.

REFRIGERATOR OF THE ABSORPTION TYPE Filed Dec. 17, 194'7V /J A Hmm MNHN A wm June 3, 1952 N, E, wlDELL REFRIGERATOR 0F THE ABSORPTION TYPE 2 SHEETS-SHEET 2 Filed Dec. 17, 1947 L L M L Wz/L WL f L Patented June 3, 1952 orifice REFRIGERATOR F TH ABSORPTION TYPE Nils Erik widen, stockholm,l sweden, assigner 'to Aktiebolaget Elektrolux, Stockholm,

corporation of Sweden v Application December 17, 1947, Serial No. 792,136 Irl Swd December 19, 1946 4; Claims'. (Cl. 62119.5)

My invention relates to refrigerators of the absorption type, and more particularly to cooling of a storage compartment of arefrigerator with the aid of a refrigeration system 'employing .evaporation of refrigerant fluid in the presence ofv an inert gas or auxiliary agent.

It is anobject of my invention to effect im-i provements in cooling a storage compartment of a refrigerator by a refrigeration system of the inert gas type, particularly to provide a cooling element for such a system which will make available a maximum amount of usable storage space in the compartment.

Another object of my invention is to provide such a cooling element which can be inserted into and removed from the storage compartment through an opening in a thermally insulated wall thereof which is of minimum size, thereby reducing the tendency for heat transfer into the vcom partment at the closure member employed to close the wall opening and promoting efficient cooling of the compartment by the cooling element. y j

The above and other objects and advantages of the invention will be better understood from the f ollowing description taken in connection with the accompanying drawings forming a part of this specic'ation, and in which Fig, 1 is a view more or less diagrammatically illustrating anl absorption refrigeration system of the inert gas'type in which the invention is embodied; Fig. 2 isv af fragmentary vertical sectional Viewv of a refrigerator and cooling element 'therefor which embodies the invention and is associated with a refrigeration system like that shown in Fig. 1; Fig. 3 is a lfio'ri# zontal sectional view taken at line 3-3 of Fig.' 2 to show details more clearly, the cooling velernent being seenv in top plan View; Figs. 4 and 5 are top plan viewsl of cooling elements illustratngmodifi'- cations of the embodimentvshow'n in Figs. 2 andt; Fig. Gis a front'view in elevation of a cooling ele-j ment illustrating a still further modifcationV of the invention in whichprovision is made for freezing ice'cubes and the like; and Fig. v7 Vis a vertical sectional view of a cooling element illus'- trating a still further modification of the invention.

In Fig. 1 I have shown my invention in connection with an absorptionrefrigeration system of a uniformy pressure type which is well known in the art and in which an inert pressure equalizing gas is employed. Such a refrigeration system' comprises a generator or boiler I0 containing'A a' refrigerant, such as ammonia, in solution ina body of absorption liquid, such as water. Heat may be Sweden, a

Y 2 supplied to the boiler II) from a heating-tube or flue II' thermally connected therewith, as by welding. The heating tube II may be heated in any suitable manner, as by a liquid or gaseous fuel burner I2, for example, which is adapted to projecty its flame into the lower end of the tube.

The heat supplied to the boiler I0 and its contents expels refrigerant vapor out of solution, and the vapor thus lgenerated flows to an air cooled condenser I4 in which it is condensed and liquefied; Liquid refrigerant flows from condenser I4 through a conduit I5 into a cooling element I6 in which it evaporates and diffuses into an inert pressure equalizing gas, such as hydrogen, which enters the lower part thereof from a gas heat exchanger I'I. Due to evaporation of refrigerant fluid into inertgas, a refrigerating effect is producedV with 'consequent absorption of heatfrom the surroundings.

The rich gas mixture of refrigerant vapor and inert gas formed, in cooling element I6 flows from the upper part thereof through a conduit I8, gas heat exchanger I'I, conduit I9 and'absorber vessel 20 into the lower part of an absorber coil 2|. In absorber coil y 2I the rich gas mixture flows countercurrent to downwardly flowing absorp-` tion liquid which enters through a conduit 22. The absorption liquid absorbs refrigerant vapor from inert gas, and inert gas weak in refrigerant flows from the upper part of absorber coil 2l in a path of flow including the gas heat exchanger I'I into the lower part of cooling element I6.

Absorption solution flows downwardly through coil 2I into the absorber vessel 20 vand such solution, which is enriched in refrigerant, passes from the vessel through a conduit 23 and an inner passage or pipe 24 of liquid heat exchanger 25 into the-lower end of a vapor lift pipe orv tube 26 which is in thermal exchange relation with the heating tube II, as by welding. Liquid is raised by vapor-liquid lift action throughpipe 26 into the upper part of. boiler II). Refrigerant vapor expelled out of solution in boiler I0, together with refrigerant vapor entering through pipe 25, ows upwardly from the boiler to the condenser I4, as previously explained.

The outlet end of condenser It is connected by an upper extension of conduit I5 and a conduit 2l to a part of the gas circuit, as to the upper part of absorber coil 2 I, for example, so thatany inert gas which may pass through the condenser It can flow into the gas circuit. The absorption liquid from which refrigerant vapor has been expelled flows from the boiler Ill through aconnecpart of the absorber coil 2|.

tion 28, an outer pipe or passage 29 of the liquid heat exchanger and conduit 22 into the upper The circulation of absorption solution in the liquid circuit justdescribed is effected by raising of liquid through pipe 26.

In order to simplify Fig. 1, the cooling element |6 has been illustrated apart froma household refrigerator. The manner in which cooling elements of absorption refrigeration systems like that justdescribed are positioned in a storage compartment of a household refrigerator cabinet is diagrammatically shown in Figs. 2 and 3. In Figs. 2 and 3 the cooling element I6v is disposed in a storage compartment 30 of a thermally insulated cabinet 3| having a top Wall 32, rear Wall 33 and opposing side walls 34, only one of which is shown in Fig. 3.

In order to position the cooling element I6 in the storage compartment 30, the rear Wall 33 of the cabinet is formed with an opening 35 defined by a rectangular frame 36 which may beV formed of wood, for example. A cover or closure member 31 for the opening, which contains insulating material 38 and through which the conduit l5 and gas heat exchanger |1 extend, is arranged to bear against a gasket 39 of suitable insulating Vmaterial and removably secured at 40 to the rear wall 33.

While the cooling element I6 in Fig. 1 is diagrammatically shown in the form of a looped Vcoil in a single vertical plane, it shouldY be understood that this is the customary practice when schematically illustrating an absorption refrigeration system of the inert gas type. However, in cooling elements formed of piping and shaped to provide a path of flow for inert gas which extends through a substantial vertical height, it has generally been the practice heretofore to employ a looped coil having horizontally spaced apart straight portions which are disposed one above another in diiferent vertical planes and connected by horizontal as Well as vertical bends. In such cooling elements rprovision is usually made to provide supporting surfaces which are in good heat conductive relation with the spaced apart straight coil portions and bridge the gap disclosed in the Schullstrom patent are not entirely satisfactory inthat a substantial part of the storage compartment is taken Vup. by the cooling element, thereby reducing the amount of space availablefor storing foods. This is especially true in refrigeratorcabinets of small size having a storage'compartment ranging from one to three cubic feet, for example.

In accordance with my invention, in order vto i provide a maximum amount of usable storage space in the compartment 30, the cooling element lI6 comprises a looped coil having straight portions 4| one above another and connecting bends 42 disposed essentially in a single vertical plane. Asbest shown in Fig. 3, the looped coil is desirably positioned closely adjacent tov and alongside one of the Vlateral side walls 34 so thatthe compartment 30 can be eiiiciently used for a variety of different food loadings and readily accommodate articles which are of large size.

A vertically extending plate 42 having an area coextensive with that of the looped coil is secured in good thermal contact with the coil along its entire length, as by welding or brazing, for example, to provide a relatively extensive heat transfer surface over the opposing faces of which air can pass in intimate contact therewith. The plate 42 desirably is iixed to the looped coil at the side thereof removed from the side Wall 34 of the storage compartment 30, and the forward edge portion may be bent back so as to envelop fthe front connecting bends 42', as indicated at 43, thereby forming a simple arrangement for neat in appearance. f

By locating the cooling element I6 closely adjacent to one of the side walls 34 so as to form a relatively narrow passage 44 having a vertical height coextensive with that of the looped coil, the natural circulation of air, which is induced by air coming in contact with the looped coil and plate 42, is promoted. In addition, a number of vertically extending L-shaped fins 45 may be secured in good thermal contact with the plate 42, which not only increase the heat transfer surface provided by the cooling element I6 but also form a plurality of open-ended U- shaped'channels 46 which further :promotes natural circulation of air in the compartment 3|) as the result of air movement in the channels.

If desired, a plate may be provided which is of U-shaped form and in good thermal contact with both sides of the vertically extending looped coil. Such ay modication is shown in Fig. 4 in which a plate 42a envelops the forward partV and both sides of the looped coil. In addition, vertically extending L-shaped fins 45a may be secured in good thermal contact with the plate 42a at both sides of the looped coil to provide open-ended U-shaped channels 46a at opposite sides of 'the cooling element.

In certain instances it may be preferable to provide cooling elements in accord with the invention in which the L-shaped iins are secured directly to the looped coil, thereby avoiding the necessity of using plates 42 and 42a inl the embodiments of Figs. 2 and 3, respectively. Such a modification is shown in Fig. V5 in which the sides 41 of L-shaped fins 4517 more or less form a substantially continuous plate-like surface which the L-shaped fins 45 in Fig. 3.

A cooling element formedrof a looped coil in a single vertical plane readily lends itself to a construction for supporting an icetray for freezing ice and other matter. Such a modification is shown in Fig.` 6 in which two platesAZb and 42e are disposed one above another in good thermal contact with upperand Vlower portions, respectively, of the looped coil. TheV upperL plate 42b is bent back and envelopsthe uppermost straight coil portion 4|, as indicated at 48, .andr L-shaped fins 45cmay be ,secured thereto.' 'I'he bottom part of plate Y4212 is Vformed to provide a receptacle .,491 which:- is centrally disposed'. relative-'to the looped coilw.`

Therlower plate i2cv envelops the :two bottom 'straight coil portions and ns 45d arel secured thereto. The receptacle 49 isadaptedfto' receive an ice. tray Ell-.and thebottom supporting surface thereof is in goodthermal contact ywith thefup'per bent portion ofgthe bottom plate 42o, so thata good heatconductive path will be provided for abstracting heat from the contents ofA the" tray 50;'. A front Aplate 5I having an opening 52 therein throughv which the tray 50 can be inserted into and withdrawn from the receptacle 49' may be providedL at the front-of the looped coil and fixed to the cooling: elementin any lsuitable lnecessity Aof 'shaping a plate membery to form -a receptacle as 'shown in Fig. 6 and justfdescribed.

In'this modification plates 42e and42fare secured tonne side of the looped'coil and L- shaped fins 45e and 45f-in turn are xed'thereto generally in the same manner as shown in Fig. 6.

In view 'ofthe foregoing, it will now be understood that an improved cooling element or evaporator structure has-been provided for absorption refrigeration systems ofthe inert gas ktype which comprises a looped coil having substantially horizontal straight portions and connecting bends in a single vertical plane.. When such an evaporator structure is disposed in a storage compartment of a household refrigerator, especially vin a refrigerator cabinet which is relatively small inv size,v a maximum amount vof usable storage is Vprovided` in the compartment.

Further, an evaporator structure constructed in accord with the invention possesses the additional important advantage that it can be inserted into and withdrawn from the storage'compartment through an opening in a thermally insulated wall of the compartment which is of minimum size and whose height is considerably greater than its width. Such openings, which are often referred to as window openings, de-

sirably should be as small as possible to minimize the tendency for heat transfer into the storage compartment about the thermally insulated closure member which closes and seals the window opening.

In Figs. 2 and 3 it will be seen that the "window opening is relatively narrow and of such height that it will be just sufficiently large to accommodate the looped coil and heat transfer fins in thermal contact therewith. Moreover, by locating the looped coil adjacent to a lateral side wall of the storage compartment and concealing such coil from View when access is gained into the compartment by opening the door at the front of the cabinet, a cooling arrangement is obtained which is neat and attractive in appearance and permits a wide variety of food loadings. This is especially important in small cabinets having storage compartments which are about one to one and a half cubic feet in size and employed to cool bottled beverages or to store medicines, such as serums, for example. It will be seen that all of the piping or conduit means located in the compartment 30 is disposed substantially in a single vertical plane that is perpendicular to the thermally insulated wall 33 having the relatively narrow vertical extending opening 35. Hence, the entire portion of the gas circuit in the com- 6. partment 30 is vformedby piping 'which provides a pathv of flow for refrigerant uid'and' inert gas in which suchiluidsli'n their-movement therethrough always remain essentially in thesingle vertical plane.

Modincations of' the embodiments ofmy invention which I have described will occur to those skilled in the art, so that'I desire my invention not to be limited to the particular arrangements set forth and intend in the claims to coverall modifications whichdo. not depart from the spirit and scope of the invention.

: What is claimed is: 1. In a refrigerator including acabinethaving thermally insulated walls deninga storage compartment and in one of which a relatively narrow vertically extending opening is provided whose height is considerably greater than its width, vand a thermally insulated closure memberfor such opening, absorption refrigeration apparatus including piping .providingl a circuit for inert gas comprising a cooling element located in the'compartment and removable therefrom with removal ofthe closure member, the piping for said cooling element'b'eing inthe form of a looped coil in which refrigerant fluid evaporates in the presence of-'the inert-gas, and'all of the piping located'in the compartment including said looped coil being disposed essentially in a single vertical planethat is substantially perpendicular tothe thermally insulated wall having the relatively narrow vertically extending opening, said looped coil being disposed closely adjacent to and spacedrfroni a lateral side wall of the compartment and including horizontally extending straight portions at different levels and connecting vertical bends', structure in good thermal contact with said looped coil to provide a relatively extensivel heat transfer surface over which air can pass in intimate contact so as to promoteV cooling of air, anda substantially'flat memberV mounted on a straight coil portion beneath a higherY located straight coil portion and in good thermal connection therewith, said nat member being adapted to support an ice tray and extending transversely of the vertical plane of said looped coil and having a region thereof in vertical alignment with said structure providing said relatively extensive heat transfer surface.

2. In a refrigerator including a cabinet having thermally insulated walls defining a storage compartment and in one of which a relatively narrow vertically extending opening is provided Whose height is considerably greater than its width, and a thermally insulated closure member for such opening, apparatus having a circuit for inert gas which includes a cooling element located in said storage compartment and removable therefrom with removal of the closure member, said cooling element comprising a looped coil disposed essentially in a single Vertical plane Which is substantially perpendicular to the thermally insulated wall having the relatively narrow vertically extending opening and in which refrigerant uid Vevaporates in the presence of the inert gas, said looped coil being disposed closely adjacent to and spaced from a lateral side wall of the compartment, and structure in good thermal contact with said coil to provide a relatively extensive heat transfer surface, said structure being constructed and arranged to provide a number of open-ended vertically extending channels coextensive in height with said coil to promote natural circulation of air induced by air coming in contact with the surfaces of said coil and channels.

3'. In a refrigerator including a cabinet having thermally insulated walls defining a storageV compartment and in one of whicha relatively narrow vertically extending opening `is provided whose height is considerably greater than its width,` and a thermally insulated closure member for such opening, absorption refrigeration apparatus including piping providing a circuit for inert gas comprising a cooling element located in the compartment and removable therefrom with removal of the closure member, the piping for said cooling element being in the formof a looped coil in which refrigerant fluid evaporates in the presence of the inert gas, andall of thepiping located in the compartment including said looped coil being disposed essentially in a single vertical plane that is substantially perpendicular tothe thermally insulated wall having the relatively narrow vertically extending opening, said looped coil includingv horizontally extending straight portions one above the other and connecting bends, structurek including a vertically extending part in good thermal contact with Va plurality of Vportions of said coil, and a plate mounted on the lower of said adjacent straight coil portions at the gap and in good thermal connection therewith, said plate being adapted to support an ice tray and extending transversely of the vertical plane of said looped coil and having a region thereof in vertical alignment with said vertically extending part providing the relatively extensive heat transfer surface.

4. Ina refrigerator including a cabinet having thermally insulated walls deiining a storage compartment and in one of .which a relatively narrow vertically extending opening is provided whose height is considerably greater than its width, and a thermallyinsulated closure member for such ing horizontally vextending straight portions one above another and connecting bends, and structure including a horizontally disposed part in good thermal contact with a-horizontally extending straight portion which is beneath the uppermost straight portion of said coil for supporting an ice tray and the like and a vertically extending part in good thermal contact with a plurality of straight portions at different levels and over which air can pass in intimate contact therewith, said vertically extending part being entirely below and in good thermal connection with said .Y

horizontally extending part.

NILS ERIK WIDELL.

v REFERENCES CITED The `following references are of record in the iileof this patent:

UNITED STATES PATENTS Number Name y Date 1,594,532 LabusV ;1 Aug. 3, 1926 2,129,982 Ashby Sept. 13, 1938 2,154,258 Y Backstrom Apr. 11, 1939 2,211,713 Bergholm 1 Aug. 13, 1940 2,261,683 Kuenzli 1--.' Nov. 4, 1941 2,263,067 Berggrabe Nov. 18, 1941 2,319,601 Hedlund May 18, 1943 2,337,653 Ehnbom Dec. 28, 1943 2,407.733 Ashby ---1 Sept. 17, 1946

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